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Polyethylene glycol promotes autoxidation of cytochrome c
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| Title: | Polyethylene glycol promotes autoxidation of cytochrome c |
| Authors: | Sato, Wataru Browse this author | | Uchida, Takeshi Browse this author →KAKEN DB | | Saio, Tomohide Browse this author | | Ishimori, Koichiro Browse this author →KAKEN DB |
| Keywords: | Heme | | Cytochrome c | | Electron transfer | | Dehydration |
| Issue Date: | Jun-2018 |
| Publisher: | Elsevier |
| Journal Title: | Biochimica et Biophysica Acta (BBA) - General Subjects |
| Volume: | 1862 |
| Issue: | 6 |
| Start Page: | 1339 |
| End Page: | 1349 |
| Publisher DOI: | 10.1016/j.bbagen.2018.03.010 |
| Abstract: | Cytochrome c (Cyt c) was rapidly oxidized by molecular oxygen in the presence, but not absence of PEG. The redox potential of heme c was determined by the potentiometric titration to be +236 ± 3 mV in the absence of PEG, which was negatively shifted to +200 ± 4 mV in the presence of PEG. The underlying the rapid oxidation was explored by examining the structural changes in Cyt c in the presence of PEG using UV–visible absorption, circular dichroism, resonance Raman, and fluorescence spectroscopies. These spectroscopic analyses suggested that heme oxidation was induced by a modest tertiary structural change accompanied by a slight shift in the heme position (<1.0 Å) rather than by partial denaturation, as is observed in the presence of cardiolipin. The near-infrared spectra showed that PEG induced dehydration from Cyt c, which triggered heme displacement. The primary dehydration site was estimated to be around surface-exposed hydrophobic residues near the heme center: Ile81 and Val83. These findings and our previous studies, which showed that hydrated water molecules around Ile81 and Val83 are expelled when Cyt c forms a complex with CcO, proposed that dehydration of these residues is functionally significant to electron transfer from Cyt c to CcO. |
| Rights: | © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ | | http://creativecommons.org/licenses/by-nc-nd/4.0/ |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/72937 |
| Appears in Collections: | 理学院・理学研究院 (Graduate School of Science / Faculty of Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 内田 毅
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